Smithsonian Report, 1899.— Roscoe. 



Plate III. 



-Z^-^^ytU.^ M-^^^-^^te^ 



^;e»^^^ ^:^^<^ 



J^'-T^^ 



^z^ -^^ -^ 



^^^>t^A^^ 



^ 





<^^^€>^ 



^^^^^ 



^---^A-^^ (?i^-^^;S^^^^.^--^ >^ 





Facsimile of Letter of R. W. Bunsen, 1859. 



